1. Field of the Invention
The invention relates to a drive for a printing group of a rotary printing machine.
2. Discussion of the Prior Art
European reference EP 0 644 048 A2 discloses the drive of a printing group that contains a form cylinder and a transfer cylinder. The printing group has its own motor, which drives the transfer cylinder via a toothed belt drive. The transfer cylinder and the form cylinder are in drive connection via cylinder gears on their journals. This reference also mentions the direct coupling or a gearwheel coupling of the motor to the transfer cylinder.
A direct coupling of a transfer cylinder to an electric motor is disclosed by European reference EP 0 621 133 A1. For readjustment during movements into and out of the ready-to-print position, the stator is eccentrically mounted in the same fashion as the transfer cylinder. During adjustment, these eccentric bushings are also activated. A device of this type is expensive.
In a gearwheel coupling of the drive motor, drive-in by a drive spur gear into the cylinder gear of the transfer cylinder is conceivable. During movements of the transfer cylinder into the shut-off position, which movements take the form of swiveling motions around the form cylinder, the center-to-center distance to the drive spur gear is disadvantageously influenced. The gearwheels have too little overlap or can slip completely out of engagement.